Planetary health diet: dissecting the link between diet, mortality risk and heart age from a 16-year follow-up of the Guangzhou Biobank Cohort Study.

Abstract

To examine the associations of planetary health diet (PHD) with all-cause and cause specific mortality, alongside heart age based on the Guangzhou Biobank Cohort Study (GBCS) and conduct mediation analysis. Participants were recruited from the GBCS and were aged ≥ 50 years. Dietary information was collected using a validated Food Frequency Questionnaire. Participants were assigned PHD scores between 0 (no adherence to PHD) and 140 (complete adherence to PHD). Primary outcomes were all-cause, cardiovascular disease (CVD) and cancer mortality. Causes of death were identified through death registry. Secondary outcome, heart age, was calculated using sex-specific 10-year CVD risk prediction models previously developed and validated in the GBCS. Cox proportional hazards regression and linear regression were used to analyze the associations of PHD scores with mortality and heart age. Mediation analyses were conducted using the difference method implemented by the "mediate" SAS macro. Of 25,550 participants aged 50+ years, during 417,590 person-years of follow-up, higher PHD scores was linearly associated with lower all-cause and CVD but not cancer mortality (hazard ratio (HR) (95% confidence interval (CI)) per 10-point increment: 0.94 (0.92-0.97), 0.92 (0.89-0.95) and 0.97 (0.93-1.01)). The association with all-cause mortality was mediated by white blood cell count (WBC), waist-to-hip ratio and waist-to-hip-to-height ratio (mediation proportion (95% CI): 6.2% (3.2-11.7%), 2.6% (0.9-7.2%) and 5.4% (2.8-9.9%)), whereas the association with CVD mortality was mediated by WBC and waist-to-hip-to-height ratio (7.9% (4.1-14.9%) and 7.4% (3.0-17.0%)). A negative association between PHD scores and heart age was observed in women but not in men (β (95% CI) per 10-point increment: - 0.13 (- 0.24, -0.01) and 0.05 (- 0.15, 0.25) years, P interaction < 0.001). Higher adherence to PHD was linearly associated with lower all-cause and CVD but not cancer mortality in Chinese aged 50+ years, and with lower heart age in women only. Our findings advocate for PHD in middle-aged to older Chinese, particularly women to improve cardiovascular health.